Females May Be Naturally More Prone to Stress: Animal Study

by -- Alan MozesUpdated: Jun 15th 2010

TUESDAY, June 15 (HealthDay News) -- When it comes to stress, women are twice as likely as men to develop stress-induced disease, such as depression and/or post-traumatic stress, and now a new study in rats could help researchers understand why.

The team has uncovered evidence in animals that suggests that males benefit from having a protein that regulates and diminishes the brain's stress signals -- a protein that females lack.

What's more, the team uncovered what appears to be a molecular double-whammy, noting that in animals a second protein that helps process such stress signals more effectively -- rendering them more potent -- is much more effective in females than in males.

The differing dynamics, reported online June 15 in the journal Molecular Psychiatry, have so far only been observed in male and female rats.

However, Debra Bangasser of the Children's Hospital of Philadelphia and colleagues suggest that if this psychopathology is ultimately reflected in humans it could lead to the development of new drug treatments that target gender-driven differences in the molecular processing of stress.

In a news release from the journal's publisher, the study authors explained that the identified protein differences relate to the alternate ways male and female rats respond to the brain's secretion of a molecule called corticotropin-releasing factor (CRF).

CRF, they pointed out, controls the body's response to stress. When the researchers injected rats with CRF it took less of the molecule to excite the female rats than the male rats. The authors attributed this to a protein -- present in both genders -- that works to bind with CRF more effectively in female rats, thus elevating their stress sensitivity.

Male rats, on the other hand, were also better able to handle stress because of a second protein they possess that is absent in female rats. This protein allows male rats to "internalize" stress exposure by cutting back on the number of cell membrane receptors they make available for CRF binding, thereby reducing the molecule's impact.